Antibacterial anti-mite hydrophobic polylactic acid fiber fabric and preparation method thereof

Abstract

The invention provides an antibacterial anti-mite hydrophobic polylactic acid fiber fabric and a preparation method thereof, the preparation method comprises the following steps: S1, dispersing polylactic acid and an inorganic antibacterial anti-mite agent in a solvent, and spinning the obtained spinning solution into a nanofiber membrane; s2, adding a hydrophobic agent into water, and stirring to obtain modified liquid; polylactic acid fiber fabric subjected to plasma treatment in advance is soaked in the modification liquid, ultrasonic treatment and drying are carried out, and modified fabric is obtained; s3, performing ultrasonic compounding on the nanofiber membrane and the modified fabric. The inorganic antibacterial and anti-mite agent is added into the spinning solution, so that the prepared nanofiber membrane can be endowed with antibacterial and anti-mite effects; the fabric is treated by plasma, so that the binding strength between the hydrophobic agent and the fabric can be improved, the hydrophobic property of the fabric is ensured, and the washable stability of the hydrophobic property is improved; the nanofiber membrane and the modified fabric are subjected to ultrasonic compounding, so that the hydrophobic performance and the antibacterial and anti-mite performance of the fabric can be ensured, and adverse effects on the biodegradability of the fabric are avoided.

Description

Technical Field

[0001] This application relates to the field of textile technology, and in particular to an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric and its preparation method. Background Technology

[0002] With increasing health awareness, the demand for antibacterial, anti-mite, and easy-to-clean textiles is growing. Polylactic acid (PLA) fiber is a synthetic fiber made from biomass such as corn and straw, through microbial fermentation to produce lactic acid, followed by polycondensation and melt spinning. PLA fiber boasts advantages such as high strength, good extensibility, excellent resilience, soft hand feel, excellent drape, complete biodegradability, and good skin compatibility, making it widely used in clothing, home textiles, and other fields.

[0003] In related technologies, the preparation of antibacterial, anti-mite, and easy-to-clean polylactic acid (PLA) fiber fabrics mainly involves the following two methods: (1) Surface functional finishing: This method uses coating and other technologies to form a hydrophobic coating on the surface of the PLA fiber fabric, giving the fabric hydrophobic (i.e., waterproof and stain-resistant) properties, and by adding antibacterial and anti-mite agents such as nano-silver to the coating, the fabric is given antibacterial and anti-mite effects. However, antibacterial and anti-mite agents such as nano-silver are easily precipitated during the washing process, and the durability of the antibacterial and anti-mite effects is not good; (2) Functional masterbatch blending and spinning: This method involves melting and blending antibacterial and anti-mite agents with PLA chips to make functional masterbatches, and then spinning them to make fabrics. However, functional masterbatches are prone to agglomeration, clogging the spinning filtration system and affecting the spinning efficiency; in addition, antibacterial and anti-mite agents are usually inorganic materials, and inorganic materials have poor compatibility with PLA, which easily forms interface defects, leading to stress concentration, reducing the toughness of the fiber, resulting in a stiff hand feel and reduced drape of the fabric. Summary of the Invention

[0004] This application provides an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric and its preparation method to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of this application is as follows: This application provides a method for preparing an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric, the method comprising the following steps: S1. Disperse polylactic acid and inorganic antibacterial and anti-mite agents in a solvent to obtain a spinning solution, and spin the spinning solution into a nanofiber membrane; S2. Add a hydrophobic agent to water, stir, and obtain a modified solution; The pre-plasma-treated polylactic acid fiber fabric is immersed in the modified liquid, ultrasonically treated, and dried to obtain the modified fabric. S3. The nanofiber membrane is ultrasonically composited with the modified fabric to obtain the antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric.

[0006] In one embodiment of this application, in step S1, the mass ratio of the inorganic antibacterial and anti-mite agent to the polylactic acid is 0.1-0.5:8-14, preferably 0.2-0.5:9-14.

[0007] In one embodiment of this application, in step S1, the inorganic antibacterial and anti-mite agent is selected from at least one of nano zinc oxide, nano copper oxide, nano titanium dioxide, nano zinc sulfide, nano cadmium sulfide and nano molybdenum disulfide.

[0008] In one embodiment of this application, in step S1, dispersion is carried out at a temperature of 22-27°C.

[0009] In one embodiment of this application, in step S1, the dispersion time is 3-5 hours, preferably 3.5-5 hours.

[0010] In one embodiment of this application, in step S1, the spinning solution is spun into a nanofiber membrane using electrospinning.

[0011] In one embodiment of this application, in step S1, during the electrospinning process, the voltage is 10-20kV, preferably 15-20kV; the spinning speed is 1-3mL / h, preferably 2-3mL / h.

[0012] In one embodiment of this application, in step S1, the thickness of the nanofiber membrane is 5-30 μm, preferably 10-20 μm.

[0013] In one embodiment of this application, in step S2, the power of the plasma is 50-150W, preferably 60-150W.

[0014] In one embodiment of this application, in step S2, the straight-line distance between the plasma emission point and the polylactic acid fiber fabric is 1-5 mm, preferably 1-4 mm.

[0015] In one embodiment of this application, in step S2, the plasma treatment time is 5-15s, preferably 6-15s.

[0016] In one embodiment of this application, in step S2, the mass ratio of the hydrophobic agent to water is 5-30:1000, preferably 10-30:1000.

[0017] In one embodiment of this application, in step S2, during the impregnation process, the bath ratio is 1:20-40, preferably 1:25-40.

[0018] In one embodiment of this application, in step S2, the power of the ultrasound is 15-150W, preferably 50-90W.

[0019] In one embodiment of this application, in step S2, the stirring time is 30-90 minutes, preferably 45-90 minutes.

[0020] In one embodiment of this application, in step S2, the drying temperature is 55-65°C, preferably 58-63°C; and the drying time is 5-8 hours, preferably 6-8 hours.

[0021] In one embodiment of this application, in step S3, the frequency of the ultrasonic composite is 15-20kHz, preferably 16-18kHz; the power of the ultrasonic composite is 2000-3000W, preferably 2200-2600W; and the welding pressure of the ultrasonic composite is 50-200 N, preferably 80-140N.

[0022] This application also provides an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric prepared according to the method described above.

[0023] The beneficial effects of this application are: This application imparts antibacterial and anti-mite properties to the prepared nanofiber membrane by adding an inorganic antibacterial and anti-mite agent to the spinning solution. Plasma treatment of the polylactic acid fiber fabric improves the bonding strength between the hydrophobic agent and the fabric during subsequent processing, enhancing the fabric's hydrophobic properties while improving its wash resistance stability. Ultrasonic bonding of the nanofiber membrane with the modified fabric obtained after hydrophobic modification ensures the bonding strength between the two, thereby guaranteeing the fabric's hydrophobic and antibacterial / anti-mite properties without adversely affecting its biodegradability. This also avoids the technical problem of clogging the spinning filtration system and affecting spinning efficiency caused by using functional masterbatches to prepare antibacterial and anti-mite fabrics in existing technologies.

[0024] In this application, by ultrasonically treating polylactic acid fiber fabric, the adhesion between the nanofiber membrane and the modified fabric can be improved, so that the finished fabric has antibacterial and anti-mite effects, hydrophobic effect and comfort. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] One embodiment of this application provides a method for preparing an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric, which includes the following steps: S1. Disperse polylactic acid and inorganic antibacterial and anti-mite agents in a solvent to obtain a spinning solution, and spin the spinning solution into a nanofiber membrane; S2. Add a hydrophobic agent to water, stir, and obtain a modified solution; The pre-plasma-treated polylactic acid fiber fabric is immersed in a modifying solution, ultrasonically treated, and dried to obtain the modified fabric. S3. The nanofiber membrane is ultrasonically composited with the modified fabric to obtain an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric.

[0027] This application imparts antibacterial and anti-mite properties to the prepared nanofiber membrane by adding an inorganic antibacterial and anti-mite agent to the spinning solution. Plasma treatment of the polylactic acid fiber fabric improves the bonding strength between the hydrophobic agent and the fabric during subsequent processing, enhancing the fabric's hydrophobic properties and its wash resistance stability while maintaining its hydrophobicity. Ultrasonic bonding of the nanofiber membrane with the modified fabric obtained after hydrophobic modification ensures the bonding strength between the two, thereby guaranteeing the fabric's hydrophobic and antibacterial / anti-mite properties without adversely affecting its biodegradability. This also avoids the technical problem of clogging the spinning filtration system and affecting spinning efficiency caused by using functional masterbatches to prepare antibacterial and anti-mite fabrics in existing technologies.

[0028] In one embodiment of this application, in step S1, the concentration of polylactic acid in the spinning solution is 8wt%-14wt%, preferably 10wt%-14wt%. The mass ratio of the inorganic antibacterial and anti-mite agent to polylactic acid is 0.1-0.5:8-14, preferably 0.2-0.5:9-14. The inorganic antibacterial and anti-mite agent is selected from at least one of nano zinc oxide, nano titanium dioxide, nano copper oxide, nano zinc sulfide, nano cadmium sulfide, and nano molybdenum disulfide. The solvent is selected from halogenated hydrocarbons. Examples of halogenated hydrocarbons include chloroform, trichloroethane, tribromomethane, and tribromoethane.

[0029] In one embodiment of this application, in step S1, dispersion is carried out at a temperature of 22-27°C; the dispersion time is 3-5 hours, preferably 3.5-5 hours.

[0030] In one embodiment of this application, in step S1, the spinning solution is spun into a nanofiber membrane using electrospinning. During electrospinning, the voltage is 10-20 kV, preferably 15-20 kV; the spinning speed is 1-3 mL / h, preferably 2-3 mL / h. The thickness of the nanofiber membrane is 5-30 μm, preferably 10-20 μm.

[0031] In one embodiment of this application, in step S2, the plasma power is 50-150W, preferably 60-150W. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric is 1-5mm, preferably 1-4mm. The plasma treatment time is 5-15s, preferably 6-15s.

[0032] In one embodiment of this application, in step S2, the mass ratio of the hydrophobic agent to water is 5-30:1000, preferably 10-30:1000. The hydrophobic agent includes, but is not limited to, substances such as polydimethylsiloxane (PDMS) and polymethylhydrosiloxane (PMS). The stirring time is 30-90 minutes, preferably 45-90 minutes. During the impregnation process, the bath ratio is 1:20-40, preferably 1:25-40.

[0033] In one embodiment of this application, in step S2, the ultrasonic power is 15-150W, preferably 50-90W. The ultrasonic treatment time is 5-10 minutes, preferably 8-10 minutes.

[0034] In this application, by ultrasonically treating polylactic acid fiber fabric, the adhesion between the nanofiber membrane and the modified fabric can be improved, so that the finished fabric has antibacterial and anti-mite effects, hydrophobic effect and comfort.

[0035] In one embodiment of this application, in step S2, the drying temperature is 55-65°C, preferably 58-63°C; the drying time is 5-8 hours, preferably 6-8 hours.

[0036] In one embodiment of this application, in step S3, the frequency of ultrasonic composite is 15-20kHz, preferably 16-18kHz; the power of ultrasonic composite is 2000-3000W, preferably 2200-2600W; and the welding pressure of ultrasonic composite is 50-200N, preferably 80-140N.

[0037] Another embodiment of this application provides an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric prepared according to the method described above.

[0038] It should be understood that the technical solutions of the various embodiments in this application can be combined with each other, but only if they are based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0039] In the following examples and comparative examples, chloroform was purchased from Sinopharm Chemical Reagent Co., Ltd.; polylactic acid was purchased from NatureWorks, Inc., USA, with a weight-average molecular weight of 130,000 g / mol; polydimethylsiloxane was purchased from Zhengzhou Gaike Technology Co., Ltd., model B1003; and the perfluorinated finishing agent was purchased from Zhejiang Fupusheng New Material Co., Ltd., model HOLPOSON® ECORING BO.

[0040] Example 1 S1. Polylactic acid and nano zinc oxide are added to chloroform at 25°C. The mass ratio of nano zinc oxide to polylactic acid is 0.2:12. The mixture is stirred for 4 hours to obtain a spinning solution with a polylactic acid concentration of 12wt%. The spinning solution was spun into a nanofiber membrane with a thickness of 14 μm by electrospinning under the conditions of 15 kV voltage and 1 mL / h spinning speed; S2. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 20:1000 and stir with a mechanical stirrer for 60 min to obtain a modified solution with a concentration of 20 g / L of polydimethylsiloxane. A 100W atmospheric pressure plasma was used to treat polylactic acid fiber fabric (commercially available, the polylactic acid fiber fabric is a twill woven fabric) for 8 seconds. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric was 3mm, and the pre-treated fabric was obtained. The pretreated fabric was immersed in the modified liquid at a liquor ratio of 1:25 and ultrasonically treated for 6 minutes at an ultrasonic power of 65W. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 6 hours to obtain the modified fabric. S3. The nanofiber membrane and the modified fabric are ultrasonically composited at a frequency of 17kHz, a power of 2400W and a welding pressure of 110N to obtain an antibacterial, anti-mite and hydrophobic polylactic acid fiber fabric.

[0041] Example 2 S1. Add polylactic acid and nano zinc oxide to chloroform at 25°C. The mass ratio of nano zinc oxide to polylactic acid is 0.1:10. Stir for 3 hours to obtain a spinning solution with a polylactic acid concentration of 10wt%. The spinning solution was spun into a nanofiber membrane with a thickness of 20 μm by electrospinning under the conditions of 10 kV voltage and 2 mL / h spinning speed; S2. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 5:1000 and stir with a mechanical stirrer for 30 minutes to obtain a modified solution with a concentration of 5 g / L of polydimethylsiloxane. A 50W atmospheric pressure plasma was used to treat polylactic acid fiber fabric (commercially available, the polylactic acid fiber fabric is a twill woven fabric) for 5 seconds. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric was 1mm, and the pre-treated fabric was obtained. The pretreated fabric was immersed in the modified liquid at a liquor ratio of 1:20 and ultrasonically treated for 5 minutes at 90W ultrasonic power. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 5 hours to obtain the modified fabric. S3. The nanofiber membrane and the modified fabric are ultrasonically composited at a frequency of 18kHz, a power of 2600W and a welding pressure of 140N to obtain an antibacterial, anti-mite and hydrophobic polylactic acid fiber fabric.

[0042] Example 3 S1. Add polylactic acid and nano zinc oxide to chloroform at 25°C. The mass ratio of nano zinc oxide to polylactic acid is 0.5:14. Stir for 5 hours to obtain a spinning solution with a polylactic acid concentration of 14wt%. The spinning solution was spun into a nanofiber membrane with a thickness of 10 μm by electrospinning under the conditions of 20 kV voltage and 3 mL / h spinning speed; S2. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 30:1000 and stir with a mechanical stirrer for 90 min to obtain a modified solution with a concentration of 30 g / L of polydimethylsiloxane. A 150W atmospheric pressure plasma was used to treat polylactic acid fiber fabric (commercially available, the polylactic acid fiber fabric is a twill woven fabric) for 15s. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric was 5mm, and the pre-treated fabric was obtained. The pretreated fabric was immersed in the modified liquid at a liquor ratio of 1:40 and ultrasonically treated for 10 minutes at 50W ultrasonic power. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 8 hours to obtain the modified fabric. S3. The nanofiber membrane and the modified fabric are ultrasonically composited at a frequency of 16kHz, a power of 2200W and a welding pressure of 80N to obtain an antibacterial, anti-mite and hydrophobic polylactic acid fiber fabric.

[0043] Example 4 S1. Add polylactic acid and nano zinc oxide to chloroform at 25°C. The mass ratio of nano zinc oxide to polylactic acid is 0.3:13. Stir for 4 hours to obtain a spinning solution with a polylactic acid concentration of 13wt%. The spinning solution was spun into a nanofiber membrane with a thickness of 17 μm by electrospinning under the conditions of 16 kV voltage and 2 mL / h spinning speed; S2. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 24:1000 and stir with a mechanical stirrer for 50 min to obtain a modified solution with a concentration of 24 g / L of polydimethylsiloxane. A 110W atmospheric pressure plasma was used to treat polylactic acid fiber fabric (commercially available, the polylactic acid fiber fabric is a twill woven fabric) for 13s. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric was 3mm, and the pre-treated fabric was obtained. The pretreated fabric was immersed in the modified liquid at a liquor ratio of 1:35 and ultrasonically treated for 9 minutes at an ultrasonic power of 75W. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 4 hours to obtain the modified fabric. S3. The nanofiber membrane and the modified fabric are ultrasonically composited at a frequency of 16kHz, a power of 2500W and a welding pressure of 120N to obtain an antibacterial, anti-mite and hydrophobic polylactic acid fiber fabric.

[0044] Comparative Example 1 S1. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 20:1000 and stir with a mechanical stirrer for 30 min to obtain a modified solution with a concentration of 20 g / L of polydimethylsiloxane (PDMS). The polylactic acid fiber fabric was treated with 100W atmospheric pressure plasma for 8 seconds. The straight-line distance between the plasma emission point and the polylactic acid fiber fabric was 3mm, and the pretreated fabric was obtained. The pretreated fabric was immersed in the modified liquid at a liquor ratio of 1:25 and ultrasonically treated for 6 minutes at an ultrasonic power of 65W. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 6 hours to obtain an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric.

[0045] Comparative Example 2 S1. Add polydimethylsiloxane (PDMS) to deionized water at a mass ratio of 20:1000 and stir with a mechanical stirrer for 30 min to obtain a modified solution with a concentration of 20 g / L of polydimethylsiloxane (PDMS). The polylactic acid fiber fabric was immersed in the modified solution at a liquor ratio of 1:25 and ultrasonically treated for 6 minutes at an ultrasonic power of 65W. The ultrasonically treated fabric was placed in an oven and dried at 60°C for 6 hours to obtain an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric.

[0046] The difference between this comparative example and Comparative Example 1 is that the polylactic acid fiber fabric was not treated with plasma.

[0047] Comparative Example 3 The difference between this comparative example and Comparative Example 1 is that a perfluorinated finishing agent is used instead of polydimethylsiloxane (PDMS), and anhydrous ethanol is used instead of deionized water.

[0048] Performance testing The surface hydrophobic angles (i.e., surface hydrophobic angles before washing) of the fabrics prepared in Examples 1-4 and Comparative Examples 1-3 were tested. Specifically, static water contact angle tests were performed on each sample using a contact angle meter. The droplet volume was 5 μL and the injection rate was 2 μL / s. The results are shown in Table 1. Then, the samples were washed according to the A1M procedure in GB / T 12490-2014 Textiles - Tests for color fastness to household and commercial washing (using ECE phosphorus-free standard detergent). After each wash, the samples were taken out and rinsed in 100 mL of water at 40°C for 1 min. The washing was repeated 30 times. After the last wash, the samples were dried and the surface hydrophobic angle (i.e., surface hydrophobic angle after washing) of each sample was tested again according to the above method. The results are shown in Table 1. The antibacterial rates of the fabrics prepared in Examples 1-4 and Comparative Examples 1-3 against Escherichia coli and Staphylococcus aureus were tested by a third-party organization. The results are shown in Table 1. According to GB / T 24253-2009 Evaluation of anti-mite performance of textiles, the fabrics prepared in Examples 1-4 and Comparative Examples 1-3 were tested for the inhibition rate (i.e., mite suppression rate) against dust mites. The results are shown in Table 1. The biodegradation rates of the fabrics prepared in Examples 1-4 and Comparative Examples 1-3 under 180 days of composting were tested according to GB / T 19277.1-2011 General method for determining the final aerobic biodegradability of materials under controlled composting conditions. The results are shown in Table 1.

[0049] Table 1 Test Results

[0050] Table 1 shows that the fabrics prepared in Examples 1-4 all exhibited antibacterial rates ≥95% against Escherichia coli and Staphylococcus aureus, mite inhibition rates ≥95%, biodegradability rates ≥93%, and surface hydrophobic angles (before washing) >145°, with no significant changes in surface hydrophobic angles before and after washing. These results demonstrate that by adding inorganic antibacterial and anti-mite agents to the spinning solution, this application can impart antibacterial and anti-mite effects to the prepared nanofiber membrane. Plasma treatment of the polylactic acid fiber fabric can improve the bonding strength between the hydrophobic agent and the fabric during subsequent processing, ensuring the fabric's hydrophobic properties while enhancing its wash resistance stability. Ultrasonic bonding of the nanofiber membrane with the modified fabric obtained after hydrophobic modification treatment ensures the bonding strength between the two, thereby guaranteeing the fabric's hydrophobic and antibacterial / anti-mite properties without adversely affecting its biodegradability.

[0051] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A method for preparing an antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric, characterized in that, The preparation method of the antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric includes the following steps: S1. Disperse polylactic acid and inorganic antibacterial and anti-mite agents in a solvent to obtain a spinning solution, and spin the spinning solution into a nanofiber membrane; S2. Add a hydrophobic agent to water, stir, and obtain a modified solution; The pre-plasma-treated polylactic acid fiber fabric is immersed in the modified liquid, ultrasonically treated, and dried to obtain the modified fabric. S3. The nanofiber membrane is ultrasonically composited with the modified fabric to obtain the antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the inorganic antibacterial and anti-mite agent to the polylactic acid is 0.1-0.5:8-14; And / or, in step S1, the inorganic antibacterial and anti-mite agent is selected from at least one of nano zinc oxide, nano copper oxide, nano titanium dioxide, nano zinc sulfide, nano cadmium sulfide and nano molybdenum disulfide.

3. The preparation method according to claim 1, characterized in that, In step S1, dispersion is carried out at a temperature of 22-27℃; And / or, in step S1, the dispersion time is 3-5 hours; And / or, in step S1, the spinning solution is spun into a nanofiber membrane by electrospinning. And / or, in step S1, the thickness of the nanofiber membrane is 5-30 μm.

4. The preparation method according to claim 3, characterized in that, In step S1, during the electrospinning process, the voltage is 10-20kV and the spinning speed is 1-3mL / h.

5. The preparation method according to claim 1, characterized in that, In step S2, the power of the plasma is 50-150W; And / or, in step S2, the straight-line distance between the plasma emission point and the polylactic acid fiber fabric is 1-5 mm; And / or, in step S2, the plasma treatment time is 5-15 seconds.

6. The preparation method according to any one of claims 1 to 5, characterized in that, In step S2, the mass ratio of the hydrophobic agent to water is 5-30:1000.

7. The preparation method according to claim 1, characterized in that, In step S2, during the impregnation process, the liquor ratio is 1:20-40; And / or, in step S2, the power of the ultrasound is 15-150W.

8. The preparation method according to claim 1, characterized in that, In step S2, the stirring time is 30-90 minutes; And / or, in step S2, the drying temperature is 55-65℃, and the drying time is 5-8h.

9. The preparation method according to claim 1 or 8, characterized in that, In step S3, the frequency of the ultrasonic composite is 15-20kHz, the power of the ultrasonic composite is 2000-3000W, and the welding pressure of the ultrasonic composite is 50-200N.

10. An antibacterial, anti-mite, hydrophobic polylactic acid fiber fabric prepared according to any one of claims 1-9.

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